1. Field of the Invention
This invention relates to an energization indicator for time switch, and particularly to an improvement for an indicator indicating a supply state of electric power in an electric time switch for switching the same on or off by receiving the supply of electric power from the outside of the time switch.
2. Description of the Prior Art
In order to normally operate such a type of electric time switch (hereinafter referred to simply as "time switch"), it is required that appropriate electric power is supplied to the time switch. Furthermore it is desired to easily discriminate whether the time switch is energized or not at the time of operating the connection of load, or of setting the time to be switched. For this reason, an energization indicator lamp 2 is generally utilized in a time switch 1 as shown in FIG. 1.
Heretofore circuits shown in FIGS. 2 and 3 have been proposed as energization indicating circuits for such type of indicator as stated above.
Namely, FIG. 2 shows an example in which a neon lamp 2a is used as such energization indicator lamp. In the circuit shown in FIG. 2, a current limitation resistance 3 is connected to the neon lamp 2a, and further a motor driving circuit part 4 is connected with these resistance 3 and circuit part 4 in parallel. In this arrangement, a driving motor 8 for the time switch is driven by means of the circuit part 4.
Moreover FIG. 3 shows another example in which a light emission diode 2b is utilized as the energization indicator lamp. In the circuit shown in FIG. 3, a circuit 5 for dropping, rectifying and smoothing voltage (or dropping, rectifying and smoothing circuit) for commercial power source is connected with a current limitation resistance 3 and a light emission diode 2b in parallel on the input side thereof. In this arrangement, the output of the smoothing circuit 5 supplies electric power to a motor driving circuit part 4 and at the same time, supplies the electric power to the light emission diode 2b through the current limitation resistance 3 so that it causes the light emission diode 2b to emit light.
In the conventional examples as shown in FIGS. 2 and 3, if electric power is supplied to the time switch 1, the energization indicator lamp 2 remains lit. By such lighting, it is indicated that the time switch 1 is normally operated.
However a conventional energization indicator lamp 2 has a disadvantage as mentioned below, because the lamp indicates only the presence of power supply upon the time switch 1. For instance, in the case where a 100 V-200 V common time switch is employed, it is impossible to discriminate whether the voltage now applied is 100 V or not, but 200 V. In these circumstances, a label indicating the applied voltage has heretofore been stuck on a time switch in a suitable manner in order to discriminate the voltage applied. Therefore a troublesome operation such as renewal of the label has been required in the case where there is a change in the provision of the time switch so that the voltage supplied thereto also changes. Besides there is a danger for causing accidents due to mistakes such as missing of such label on the time switch, and erroneous application of a label thereon.